Why might acorns fall early?

Every three to five years, oak trees are known to drop their acorns early. Several theories attempt to explain this phenomenon; for example, the tree may need to preserve its energy and cannot spend the energy needed to bring the acorns to maturity.

Contrary to superstition, acorns falling prematurely from oak trees does not indicate an earlier, colder or harsher winter. Most acorns mature in late summer and begin to drop in September or October. However, specific stresses on the oak tree, such as a lack of water, a lack of nutrients and other environmental factors, can lead to acorns dropping prematurely.